As wireless technology evolves, the number and variations of wireless communication protocols increase and may encompass multiple operating modes, including half-duplex and full duplex modes, multiple frequency bands, and various transmit power levels. As a result, portable wireless communication products such as cellular telephone handsets may need to provide support for such protocols. Therefore, radio frequency (RF) architectures of wireless communication products may be complex. Further, portable wireless communication products are typically battery powered. As such, power consumption in portable wireless products may need to be as low as possible to maximize battery life. Therefore, portable wireless communication products that provide support for many wireless communication protocols may need to have low power consumption, regardless of which wireless communication protocol is being used.
A significant portion of the power used in a portable wireless communication product may be consumed by a power supply that provides power to the portable wireless communication product. The efficiency of the power supply should be as high as possible to minimize overall power consumption. Moreover, the power supply should minimize any spurious noise generated by the power supply while supplying power to noise-sensitive circuitry such as receivers and power amplifiers (PAs). Thus, there is a need for a power supply that operates efficiently without regard to operating modes, and while doing so generates a minimal amount of spurious noise.